http://www.ux1.eiu.edu/~cfib/courses/Fussell.pdf

I find this canting nonsense. The purpose of the bombs was not to
"punish" people but to stop the war. To intensify the shame Gray
insists we feel, he seems willing to fiddle the facts. The Hiroshima
bomb, he says, was dropped "without any warning." But actually,
two days before, 720,000 leaflets were dropped on the city urging
everyone to get out and indicating that the place was going to be
(as the Potsdam Declaration has promised) obliterated. Of course few left.